So today I took the plunge and bought a gallon of Evapo-Rust. Neat stuff. It was $26 and change but it seems to be working pretty well. One gallon isn't a lot but I have the swivel jaw as well as all the small pieces soaking in it, plus some small pieces for my engine. Tomorrow I'll see if I can get the base submerged in it. Also that greenish color that I suspected may be original almost certainly is. I keep finding more and more of it and a Google search turned up this-
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Parker bought out Prentiss-
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